Sciencemadness Discussion Board

Solar Heating using a Lens from a Cheap Source (Fresnel lens)

symboom - 1-5-2011 at 19:30

a cheap source of a Fresnel lens if you can get your hands on one. is an old crt tv or computer monitor. overhead projectors also need one for enlarging an transparent sheet that is projected on a wall.
cant seem to find a video on removing them from those sources if some on can post a link to one
hope this helps anyone who wants to heat things cheaply at higher temperatures i know this thing helped me alot :D

this is a great tool and investment :D except when there are clouds:(
this is what i use for when i need heating for alot of things.
i got mine from this guy i wanted a powerful one so i got it from here
http://greenpowerscience.com/FRESNELSHOP/65INCHSPOT.html
says it reaches like 3000F fully focused.
the other thing i had to make a stand for it.this is the one i got from there. other places of course like ebay probably also have some Fresnel lens'

videos showing the power of the lens
http://www.youtube.com/watch?v=uqNuaPxKsX0
melting glass
http://www.youtube.com/watch?v=_5NyZCu2d_c
melting iron
http://www.youtube.com/watch?v=sVAEfHyZW3I
melting concrete

[Edited on 2-5-2011 by symboom]

hyperkinetic - 1-5-2011 at 20:30

CRT's have Fresnel lenses? Do you mean a certain brand/model?

symboom - 1-5-2011 at 20:33

Quote: Originally posted by hyperkinetic  
CRT's have Fresnel lenses? Do you mean a certain brand/model?


http://en.wikipedia.org/wiki/Cathode_ray_tube screens
old tvs and computer monitors used to use before lcd screens
aha found it :D:D
http://www.instructables.com/id/Salvaging-the-Fresnel-Lens-f...

using a Fresnel lens
http://www.instructables.com/id/Giant-Fresnel-Lens-Deathray-...

[Edited on 2-5-2011 by symboom]

hyperkinetic - 1-5-2011 at 20:52

ahh I see. the wiki article makes no mention of Fresnel lens, they where used in projection style TVs and in LCD screen enlargers but not CRT tvs, sadly.

symboom - 1-5-2011 at 21:03

im mistaken was thinking they were in CRT's too :mad: .glad to see i answered you question. but there are people throwing away e-trash i remember there was a collection day for e-waste sad to see pallets full of old computers and big-screen tvs :(
ebay http://shop.ebay.com/i.html?_from=R40&_trksid=p5197.m570...
but im like you don't like having to order online over $200 is a lot but it is useful did not even bother with extracting a crt.
try your school maybe throwing away a overhead projector
btw spot lens are the key because they also have liner lens


[Edited on 2-5-2011 by symboom]

[Edited on 2-5-2011 by symboom]

hyperkinetic - 1-5-2011 at 21:44

School I'm well past but I will keep my eye open.

To bad CRTs don't have them. I'll have to keep my eye open for the projection style TVs that are being tossed.